A variety of methods have been empoyed to make a homogeneous solution of single bilayers vesicles. Electron microscopy and 2-photon fluorescence scanning, with Laurdan-doped membrane, have been used to estimate the homogeneous of the vesicles preparations and evaluate the various protocols. The effect phopholipid headgroups on membrane packing is being evaluated using Laurdan G-polarization and 2-photon imaging